...is far too underrepresented, IMO. In the vast majority of historical cases, a foreign conquering nobility has either been completely assimilated into the native culture within a few generations or (in cases where there was a complete restructuring of the government e.g. the Norman Conquest) there has been a kind of hybrid culture formed taking elements of conqueror and conquered. Under no circumstances has a chance inheritance by a Apad prince caused part of the Iberian penninsula to become Hungarian, nor did the Crusades cause the majority in Jerusalem to begin speaking German within a decade. It should be far more common for a King to convert to the native culture of his primary title than for peasants to change entire language and social structure. This was an age before mass education and propaganda, there was simply no mechanism for "spreading your culture".